1. Field of the Invention
The present invention relates generally to telecommunications, and more particularly to a method and system for connecting a voice band link box to a toll switch to facilitate trunk-related testing.
2. Description of the Related Art
Presently, trunk-related testing of a typical long distance telephone switch (such as a 4ESS switch toll switching system formerly available from AT&T) in a telecommunications network is performed by a technician utilizing a remotable trunk transmission unit (such as the Remote Measurement System Digital 2, or RMS-D2, unit available from AT&T). The RMS-D2 is a testing device that is wired to and forms a part of the 4ESS switch having the trunk circuit to be tested. The RMS-D2 provides the technician with the capability to monitor the communications path of the trunk under test. The testing technician is typically located at a network operating center ("NOC") designated specifically for the purpose of testing or at a remote location wherein the technician communicates with the RMS-D2 by means of a modem.
An example of a prior art testing system 10 in which a technician utilizing a tester 28 performs a trunk-related test is illustrated in FIG. 2. Testing system 10 generally includes 4ESS switch toll switches 12 and 26, tester 28, an originating access switch having a software controller TOPAS 30, and either a private branch exchange ("PBX") 32, end office ("EO") 34 or D-4 Multiplexer ("D-4 Mux") 36.
The 4ESS switch 12 has three RMS-D2 cabinets 20, 22 and 24, with each cabinet having a group of ten voice band links ("VBL"s) 44, 46 and 48, respectively. A VBL is a two-wire analog connection serving as a communications link from the RMS-D2 to the local PBX 32, EO 34 or D-4 Mux 36. Each VBL provides talk/listen and speaker communications paths to the technician. At tester 28, the talk/listen is provided via a PBX-compatible multibutton station set (not shown) allowing a full talk path and the speaker is provided via a PBX-compatible monitor speaker (not shown) allowing a monitor function only. The talk/listen and speaker capabilities allow the technician to properly evaluate and sectionalize troubles which could not otherwise be found by standard transmission testing. The PBX 32, EO 34 or D-4 Mux 36 interface by means of a two-wire analog line 38, 40 or 42, respectively, to a trunk sub-group ("TSG") 18, 16 or 14, respectively, of the 4ESS switch 12 to be tested. The TSG's 14, 16 and 18 link to the station set and monitor speaker at tester 28 through 4ESS switch 26 via a talk/listen two-wire analog line 52 and a speaker two-wire analog line 54, respectively.
To test TSG 18, 16 or 14 of 4ESS switch 12, the technician utilizing the tester 28 interfaces with the RMS-D2 via software controller TOPAS 30 over a data wide area network ("DWAN") 50. The technician instructs the RMS-D2 to access TSG 14, 16 or 18 via software controller TOPAS 30 and determine whether TSG 14, 16 or 18 is idle or in service. The technician then instructs the RMS-D2 via software controller TOPAS 30 to place an incoming call to either the technician's station set (for talk/listen if TSG 14, 16 or 18 is idle) or monitor speaker (for speaker if TSG 14, 16 or 18 is in service). Dialing instructions from software controller TOPAS 30 are sent to the RMS-D2, causing the RMS-D2 to dial out over the switched network by seizing and sending a signal via a VBL from one of the three RMS-D2 cabinets 20, 22 or 24 to PBX 32, EO 34 or D-4 Mux 36. The PBX 32, EO 34 or D-4 Mux 36 transmits the signal to TSG 18, 16 or 14, respectively, of 4ESS switch 12. The signal is then transmitted along either talk/listen two-wire analog line 52 or speaker two-wire analog line 54, depending on the technician's selection above, through another originating access switch, 4ESS switch 26, and back to tester 28. If the monitor function was selected, the technician will be able to listen to the accessed line over the monitor speaker device. If the talk/listen function was selected, the station set will ring.
Essentially, testing system 10 emulates a four-wire telephone line. However, a shortcoming of testing system 10 is that the thirty two-wire analog telephone lines from the three RMS-D2 cabinets 20, 22 and 24 for voice access for testing and data connections must be purchased from the local telephone company or obtained via an internal telephone service because the lines must be connected to 4ESS switch 12 through PBX 32 or the like. The purchase of these lines is extremely costly to the long distance carrier, and the cost is amplified by the number of 4ESS switches in the long distance network.
Referring now to FIG. 4, a prior art testing system 100 is shown in which a technician communicates with the RMS-D2 from a remote location by means of a modem. Testing system 100 generally includes a 4ESS switch 104, a telephone switching system such as AT&T Switching Network ("ASN") 102, a tester 118 and a PBX 114 or an EO (not shown).
The 4ESS switch 104 has three RMS-D2 cabinets 106, 108 and 110, with each cabinet having a single VBL 128, 130 and 132, respectively, providing a communications link to PBX 114 or the EO. The PBX 114 or the EO interfaces to tester 118 through ASN 102 by means of two-wire analog line 120. The technician is positioned at tester 118 with a computer device having a modem and Switched Message Automatic Remote Testing Software ("SMARTS") installed. SMARTS is a DOS-based PC system that allows the technician to remotely access the RMS-D2 in 4ESS switch 104 on a secured dial-up connection for the purpose of testing, although the testing is limited to transmission testing for sectionalization/specialized trouble shooting.
To perform a test, the technician located at tester 118 transmits a control command to the RMS-D2 instructing the RMS-D2 to locate, access and test a specific trunk circuit (not shown) of 4ESS switch 104. The control command is transmitted along two-wire analog line 120 to ASN 102. From ASN 102, the control command is transmitted through PBX 114 and into one of the three cabinets 106, 108 or 110 of the RMS-D2 via VBL 128, 130 or 132, respectively. When the RMS-D2 receives the control command from tester 118, the RMS-D2 "handshakes" with tester 118, i.e., acknowledges receipt of the control command and that a communication link has been established, locates and accesses the specified trunk circuit, performs the requested test on the trunk circuit and finally reports the test result back to tester 118 over the communication link.
A shortcoming of testing system 100 involves the cost associated with purchasing three two-wire analog telephone lines 128, 130 and 132 (multiplied by the number of 4ESS switches in the network) from the local telephone companies.
Finally, referring now to FIG. 6, a prior art testing system 200 which does not utilize an RMS-D2 and wherein a customer service representative located at a NOC 210 performs a verification on a 4ESS switch 202 in response to a customer's complaint that the customer is not receiving calls from a particular geographical area is illustrated. Testing system 200 generally includes 4ESS switch 202, an ASN 208, a customer site 204, a PBX 216 and NOC 210. The NOC 210 links to 4ESS switch 202 through PBX 216 via an access trunk order circuit ("ATOC") implemented particularly for this type of testing. There is one ATOC per 4ESS switch in the network (e.g., there are 135 ATOC's in the AT&T network). The ATOC 212 provides direct access to 4ESS switch 202 for call processing verification through 4ESS switch 202. The 4ESS switch 202 links to ASN 208 via a two-wire analog line 206, and to the customer site 204 from ASN 208 over a two-wire analog line 214.
As an example, the customer, who is located in New York, calls the customer service representative, who is located in Denver, and tells the customer service representative that the customer is not receiving calls from Tulsa. The customer service representative at the Denver NOC 210 makes a call over ATOC 212 through the 4ESS switch serving Tulsa, i.e., 4ESS switch 202, to a 4ESS switch (not shown) serving the New York area and over line 206 into the New York ASN 208, and finally over line 214 to New York customer site 204. The customer service representative at the Denver NOC 210, while connected to the customer, tells the customer that the customer service representative is calling the customer through Tulsa, and thus the customer should be able to receive calls from Tulsa, i.e., there is no problem with 4ESS switch 202. If, on the other hand, the customer service representative is unable to connect to the customer site 204 through 4ESS switch 202, the customer service representative will be alerted that 4ESS switch 202 is faulty.
A shortcoming of testing system 200 is the cost of purchasing and maintaining an ATOC per 4ESS switch in the telecommunications network to perform the above verification process.
3. Summary of the Invention
In accordance with the present invention, a system and method for connecting a VBL box to a telephone switch to facilitate trunk-related testing is provided. The system includes a remotable trunk transmission unit being interconnected to the telephone switch and interfacing with the testing device, a voice band link box having an input interface being interconnected to the remotable trunk transmission unit and an output interface being interconnected to a digital trunk of the telephone switch, and an output device being interconnected to the telephone switch. The testing device interfaces with the remotable trunk transmission unit and places a call by transmitting an analog signal via the remotable trunk transmission unit directed to the output device. The voice band link box receives the analog signal at its input interface, converts the analog signal to a digital signal and routes the digital signal from the output interface over the digital trunk of the telephone switch. The call is received at the output device.
The foregoing specific objects and advantages of the invention are illustrative of those that can be achieved by the present invention and are not intended to be exhaustive or limiting of the possible advantages which can be realized. Thus, these and other objects and advantages of this invention will be apparent from the description herein or can be learned from practicing this invention, both as embodied herein or as modified in view of any variations which may be apparent to those skilled in the art. For example, although the present invention is described with respect to long distance toll switches, it is understood that the present invention is equally applicable to local switches such as the 5ESS switch formerly manufactured and supplied by AT&T. Accordingly, the present invention resides in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.